Damper arrangements for air conditioning units



y 8 B. E. BIRDSALL 2,844,086

DAMPER ARRANGEMENTS FOR AIR CONDITIONING UNITS Filed May 26, 1954 v 2 Sheets-Sheet l INVENTOR.

BY 5M vJuly 22, 1958 s. E. BIRDSALL 2,844,086

DAMPER ARRANGEMENTS FOR AIR CONDITIONING UNITS INVENTOR.

By Me United Sta e P t n DAMPER ARRANGEMENTS FOR AIR CONDITIONING UNITS Bruce E. Birdsall, Cincinnati, Ohio, assignor to Carrier Corporation, Syracuse, N. Y., a corporation of Delaware Application May 26, 1954, Serial No. 432,457

11 Claims. (Cl. 98-38) This invention relates to damper arrangements and, more particularly, to a damper arrangement for an air conditioning unit to regulate supply of conditioned air to the plenum chamber of the unit.

In an air conditioning system of the type shown in Patent No. 2,363,294, granted November 21, 1944, in the name of Willis H. Carrier, a substantially constant volume of conditioned primary air is supplied from a central station to a plurality of room units placed throughout the building and is dischargedtherein at a velocity sufficient to induce room air through a coil in the unit to condition the same. supplied to the coils from a central station. It is customary to provide a damper arrangement at each room unit to regulate supply of primary air to each unit thus assuring the supply of such air in a substantially constant volume in accordance with the design of the system. Such a damper arrangement includes a sleeve attached to the plenum chamber of the unit and an adjustable butterfly within the sleeve. These arrangements are noisy in Lisa creating an undesirable and unpleasant hissing sound or low rumble as the air passes the butterfly and, frequently, fluctuations in pressure caused by the expansion of the air in the sleeve after passing the butterfly cause resonance in the sleeve thus increasing the sound level.

The chief object of the present invention is to provide a damper arrangement in which objectionable noise characteristics are reduced or eliminated.

An object is to provide a damper arrangement so designed as to in effect change the frequency of resonance thus reducing the noise level.

A further object is to provide a damper arrangement which causes less turbulence of the air and provides a more stream line air flow and smaller eddy currents.

A further object is to provide an inexpensive damper arrangement quickly installed and economical to adjust in which objectionable noise characteristics are substantially reduced or eliminated. Other objects of the invention' will be readily perceived from the following descript1on.

The attached drawings illustrate a preferred embodiment of the invention, in which Figure l is a diagrammatic view of a room unit that may be provided with a damper arrangement .of the present invention;

Figure 2 is a sectional view through the damper arrangement, the damper being placed in closed position;

Figure 3 is a view in elevation of the damper arrangement, the damper being shown in open position; and

Figure 4 is a sectional view illustrating the manner in which the damper is secured in place.

Referring to the attached drawings there is shown in Figure 1 a room unit 2 of the type employed in the system of Patent No. 2,363,294, provided with the damper arrangement 3 of the present invention. The room unit 2 generally includes a base unit which comprises a plenum chamber 4 having a nozzle plate 5 and a coil 6 through Which conditioning medium passes. The plenum 4 is Preferably conditioning medium is ice connected to a central station (not shown) to receive a supply of conditioned primary air therefrom, the primary air being discharged through the nozzles in plate 5 to induce a stream of secondary air from the area being conditioned through coil 6. The two streams are mixed and discharged from the unit into the area being treated. The base unit may be furred in or may be provided with a casing 7 containing an inlet 8 to permit secondary air to be induced through the coil into the unit and an outlet 9 through which the mixed streams may be discharged into the area being conditioned.

In order to balance the discharge of primary air into each unit of the system, the damper arrangement 3 is provided, such arrangement being best shown in Figures 2, 3, and 4. his important that the damper 3 extend into the plenum chamber 4 a distance such that its short edge is "free of the plenum wall. Damper arrangement 3 includes a sleeve 10 having an end 11 connected to the central station to receive high pressure, high velocity, conditioned air therefrom, the opposite end 12 protruding a desired distance into the plenum chamber 4.' The conditioned air flows through the sleeve 10 and is discharged into plenum chamber 4. As shown in Figure 1, 11a shows the location where damper arrangement 3 enters plenum chamber 4. The edge of the sleeve formed at end 12 extends at an angle other than a right angle to the axis of the sleeve; in other words, the protruding edge 12 forms substantially the outline of an oval inclined toward the end 11 of the sleeve. Preferably, the uppermost portion of the oval is formed by the portion of the edge which protrudes the greatest distance within the plenum chamber. I have found that the most satisfactory results, with regard to noise reduction, are attained if the direction of inclination is such that an angle falling within the range of about 55 to 65 and preferably about 62 is formed between the edge 12 and the top of the sleeve 10, when the sleeve is viewed in elevation.

A valve or damper 15 is mounted within the sleeve 10 adjacent end 12 at an angle of inclination such that when the valve is at its greatest restricting position the angle of inclination of the protruding end 12. It is desirable that the damper is mounted in 'the'sleeve as close to the inclined edge as possible. This distance may vary, of course, depending upon the diameter of the sleeve, the size and thickness of the. butterfly, etc. Damper 15 is provided with recesses 16 on opposite sides, such recesses receiving embossed portions 17 formed on opposite sides of sleeve 10. Portions 17 in effect form shaft-like members which support the damper in rotatable position. Preferably, flock or similar material is placed on the damper to provide a'further reduction in sound level when the damper is in almost closed postion.

Preferably, the upper potion of sleeve 10 in indented as shown at 17' to receive a bushing 18 peened in place on the sleeve. A rod 19 extends through the bushing and has its inner edge turned into a hook 20 adapted to en gage the eye 21 of a cotter pin fastened in the lower portion of damper 15. The exterior end of rod 19 is formed into a handle 23. Preferably, a set screw 24 extends within the bushing to contact rod 19 to hold it in fixed position thereby holding the damper 15 in selected position restricting flow of primary air through the sleeve.

It will be appreciated that butterfly 15 even in fully closed position does not completely restrict flow of air through sleeve 10 while in fully open position a portion of the damper protrudes beyond the edge of the sleeve and exerts very little or no restricting effect upon the flow of air in the sleeve.

The upper portion of the damper arrangement is shaped similarly to a nozzle to provide quiet discharge of air. By forming the lower portion of the sleeve of less length than the upper portion, resonance of the sleeve is changed in pitch or decreased so as to reduce the sound level. Air

passing between the damper and the lower portion of the sleeve is free to expand almost immediately within the plenum thus decreasing the eddies at the lower portion of the damper and thereby reducing noise characteristics. The protruding upper portion of the sleeve directs the discharged air stream outwardly from' the sleeve so that some expansion may occur before it strikes the walls of the plenum; this feature is important since a greater portion of the air stream passes between the damper and the upper portion of the sleeve. of the lower portion of the sleeve it is believed less turbulence is created since the air stream is free to expand thus reducing the eddying and surges frequently encountered at the rear of the damper.

The present invention provides an economical, easily installed damper arrangement for air conditioning systems which permits the supply of a substantially constant volume of air to a room unit without setting up objectionable noise characteristics. It is readily installed in an air conditioning system of the type described to permit the various units to be balanced in accordance with design conditions and holds its position accurately after the system has been balanced. While I have described the damper arrangement as being employed in combination with a room unit, it will be appreciated an arrangement of this type may be employed in other types of air conditioning systems, for example, in a ceiling outlet or other types of units. If desired, the damper arrangement may be employed to regulate supply of conditioned air to two or more unit plenum chambers which are connected to each other.

While I have described a preferred embodiment of the invention, it will be understood the invention is not limited thereto since it may be otherwise embodied within the scope of the following'claims.

I claim:

1. In a damper arrangement for use in an air conditioning system to regulate the discharge of conditioned air into a plenum chamber of a room unit, the combination of a sleeve adapted to protrude into the plenum chamber, one end of the sleeve being adapted to be connected to a source of high pressure, high velocity, conditioned air, said sleeve having its protruding edge extending at an angle other than a right angle to the axis of the sleeve, a butterfly damper mounted in said sleeve adjacent the protruding end of the sleeve in such manner that in fully open position a portion of the damper protrudes beyond the edge of the sleeve, said damper serving to regulate flow of air through the sleeve, and means for moving said damper.

2. An arrangement according to claim 1 in which the damper is mounted at an angle of inclination such that when it is moved to its greatest restricting position the angle of inclination is substantially the same as the angle of inclination of the protruding edge of the sleeve.

3. An arrangement according to claim 1 in which the damper is provided with opposite socketsin its edge and embossed portions are formed in opposite sides of said sleeve which fit int-o the sockets and hold the damper in rotatable position in the sleeve.

4. An arrangement according to claim 1 in which the moving means for the damper comprise a bushing secured to the sleeve, a rod terminating in a handle exteriorly of the sleeve and extending through the bushing Within By reducing the length .1

the sleeve, the opposite end of the rod terminating in a hook portion, and means connecting the hook portion to the damper.

5. An arrangement according to claim 4 in which the damper is provided with opposite sockets in its edge and embossed portions are formed in opposite sides of said sleeves which fit into the sockets and hold the damper in rotatable position in the sleeve.

6. An arrangement according to claim 1 in which the angle of inclination of the protruding end of the sleeve falls within the range of 5565 from a line drawn along the top of the sleeve.

7. An arrangement according to claim 6 in which the angle of inclination of the protruding end of the sleeve is about 62 from a line drawn along the top of the sleeve.

8. In a damper arrangement, the combination of a sleeve adapted to protrude into a plenum chamber, one end of the sleeve being adapted to be connected to a source of high pressure, high velocity, conditioned air, said sleeve having its protruding edge forming substantially the outline of an oval inclined toward the opposite end of the sleeve, a butterfly damper mounted in said sleeve adjacent the protruding end in such manner that in fully open position a portion of the damper protrudes beyond the edge of the sleeve, said damper serving to regulate flow of air through the sleeve, and means for moving the damper.

9. A damper arrangement according to claim 8 in which the portion of the edge protruding the greatest distance within a plenum chamber forms the uppermost portion of the oval.

10. A damper arrangement according to claim 9 in which the damper is mounted at an angle of inclination such that when the damper is moved to its greatest restricting position its angle of inclination is substantially the same as the angle of inclination of the edge of the sleeve.

11. In combination with the plenum chamber of an air conditioning unit which is disposed intermediate a source of supply of conditioned air and the outlet of the air conditioning unit, a damper arrangement for regulating flow of air from the source of supply into the plenum which comprises a sleeve having a portion thereof extending within the plenum chamber, one end of the sleeve being adapted to be connected to a source of high pressure, high velocity, conditioned air, the extended edge of the sleeve extending at an angle other than a right angle to the axis of the sleeve, a butterfly damper mounted in said sleeve adjacent the extended end of the sleeve in such manner that in fully open position a portion of the damp- I or protrudes beyond the edge of the sleeve, and means for moving. the damper toward openor closed positions.

References Cited in the file of this patent UNITED STATES PATENTS 833,554 Schwoll Oct. 16, 1906 1,204,713 Strainet al Nov. 14, 1916 1,763,838 Vernet June 17, 1930 1,766,876 Busby June 24, 1930 2,247,989 Carson July 1, 1941 2,363,294 Carrier Nov. 21, 1944 2,500,330 Stover Mar. 14, 1950 2,620,983 Lyman Dec. 9, 1952 2,724,320- Tutt Nov. 22, 1955 UNITED STATES PATENT OFFICE CERTIFICATE OF coRREcTmN Patent N0o 2,344,086 I a July 22, 1958 Bruce Eo Birdsall It is hereby certified that error appears in the printed specification,

of the above numbered patent requiring correction and that the said Let'Ker s Patent should read as corrected below.

Column 2;, line 4.0, after ":mclinetion" insert is substantially the same or similar to the angle of inclination. line 53, for "potion of sleeve 10 in" read portion of sleeve 10 is line 57,, after "pin" insert the numeral Km 22 e Signed and sealed this 11th day of November 1958 (SEAL) Attest:

KARL AXLINE ROBERT C. WATSON Attesting Ofi'icer Commissioner of Patents 

